Augmentation of Chinese hamster lymphocyte stimulation by cysteine.

Addition of 2-mercaptoethanol (2-ME) in a final concentration of 40 microM to Chinese hamster lymphocyte cultures results in a remarkable increase in lymphocyte proliferation. The same marked increase in lymphocyte proliferation is obtained when cysteine in a final concentration of about 4 mM is added to the cultures. Optimum lymphocyte proliferation after addition of 2-ME and different amounts of cysteine occurs on different days. The optimum time of culture depends on cysteine concentration. With higher amounts of cysteine longer culture times are needed for optimal stimulation.